Carbohydrate malabsorption in clinical routine: a prospective observational study.

BACKGROUND/AIMS: Nonspecific abdominal symptoms are a serious problem throughout the world. Among the multitude of differential diagnoses in carbohydrate malabsorption, only incomplete absorption of lactose is mentioned, while malabsorption of fructose and sorbitol--which occurs much more often, at least in the Western world--is usually not included. METHODOLOGY: During a 6-month period, all patients (n=90; 33 males, median age 45 years, range 10-81; 57 females, median age 47 years, range 15-71) who consecutively presented for H2 exhalation tests were evaluated. In addition to the test results, data were obtained from the referring physicians and from the family doctors responsible for the patients' long-term treatment regarding the role of the test results in the treatment of the patients. Finally, the patients were also asked whether any improvement in their symptoms had followed from the test results. RESULTS: Lactulose tests were normal in only 63% of the patients. As with the other sugars, at least one form of malabsorption was detected in 47 patients (52%). The malabsorption rate was 34% after lactose, 61% after fructose, and 91% after the intake of sorbitol. The referring physicians evaluated the test results as having been important in 52% of the patients, while the family doctors considered that there was some benefit for the patients in 77% of the cases. The patients themselves reported an improvement in 75% of cases. CONCLUSIONS: These data again show that carbohydrate malabsorption is an important differential diagnosis in patients with nonspecific abdominal complaints. However, the data also make it clear that caution is advisable both in establishing the indication for the tests and in interpreting the results. Despite this, carbohydrate malabsorption appears to be an underestimated problem in a considerable number of patients.